This invention relates to a drive unit assembly using an electromagnetic retarding system on an axle to produce a retarding force that works with a vehicle braking system to slow and stop the vehicle. The retarding system is also used to generate electrical energy, which is stored for use in operating various vehicle systems and may include providing driving power through electrical or hydraulic means.
Vehicles often use retarders to assist vehicle braking systems. Vehicle retarders work in conjunction with the braking system to slow and/or stop the vehicle. Vehicles that use retarders usually experience increased brake lining durability because the vehicle brakes do not need to provide the total braking force for the vehicle. Retarders are typically integrated into any of various vehicle systems. These retarders are often complex, expensive, and can create additional pollution or increase engine wear. Also, when maintenance is required the operation of other vehicle systems can be affected.
Also, because the retarders are powered by the vehicle either a separate power supply is required or less power is available to run other vehicle systems. This decreases the overall efficiency and fuel economy of the vehicle.
Thus, it is desirable to have a simplified retarding system that is incorporated into a drive train or axle to increase packaging space at the wheel ends. It is also desirable to have a retarding system that works efficiently without draining vehicle power. This will improve fuel economy for the vehicle while increasing the durability of brake lining material.
A vehicle drive unit assembly utilizes an electromagnetic retarding system that assists a vehicle braking system in slowing and stopping the vehicle. The retarding system also generates energy that is stored for later use. The drive unit assembly includes an axle extending between a pair of wheels and has a rotating member for driving the wheels. The braking system includes a brake member supported on each of the wheels and an actuator for selectively moving the brake members between an unactuated position and an actuated position. The braking system produces a braking force to slow the rotation of the wheels when the brake members are in the actuated position. The retarding system has at least one magnet supported for rotation with the rotating member and an inductor held fixed independently from the magnet. The retarding system produces a retarding force as the magnet rotates with respect to the inductor to slow the rotation of the wheels when the actuator moves the brake members to the actuated position. Additionally, as the magnets rotate with respect to the inductor, electrical energy is created and stored in an accumulator such as a battery, capacitor, or is used to power a pump for a hydraulic or pneumatic accumulator. This stored energy is released back to the vehicle drive train under certain conditions.
This unique retarding system increases brake lining durability and improves fuel economy. Also, energy generated by the magnets as the magnets rotate with respect to the inductor can be stored and used to operate various vehicle systems, which improves the overall efficiency of the vehicle.